The invention discloses a non-reference channel
passive radar networking cooperative weak
target signal level positioning method, and the method comprises the steps: firstly initializing
system parameters, and building a target echo model, which is polluted by
noise and
direct wave interference, of a non-reference channel
passive radar; then, a
complete data set is established in combination with a distributed multi-
station target echo model and an unknown
signal of a non-cooperative external
radiation source, a conditional likelihood function of the
complete data set is derived, and finally, based on an expectation maximization principle, an expectation step and a maximum step of the conditional likelihood function are executed in a loop iteration mode so as to continuously update target position
estimation and suppress
direct wave interference. And the maximum likelihood
estimation of the target position is obtained until the convergence condition of the
expectation maximization algorithm is met, and combined
direct wave suppression and target position
estimation updating are realized. The method provided by the invention solves the problems that the current
passive radar system is low in positioning precision, easy to be interfered by direct
waves, unknown in non-cooperative external
radiation source
signal, strong in dependence on a reference channel and the like in weak target detection.